package demo2;


import java.util.HashMap;
import java.util.HashSet;

public class TestHash {
    public static void main(String[] args) {
        HashSet<String> set = new HashSet<>();
        System.out.println(set.add("hello"));
        System.out.println(set.add("world"));
        System.out.println(set.remove("hello"));
        System.out.println(set.contains("hello"));
    }
    public static void main1(String[] args) {
        HashMap<String,Integer> map = new HashMap<>();
        map.put("hello",2);
        HashMap<String,Integer> map2 = new HashMap<>(19);
    }

}
